Conventionally, there is a binding component that is referred to as a binder for binding commercially available loose-leaf papers or papers punched by a punch.
Such a binding component has a configuration in which a plurality of annular ring parts is connected by a back part. Each of the ring parts divided into multiple pieces is connected by a flexible hinge portion so that the ring part can be opened and closed.
For example, JP-A-2000-289376 discloses a configuration in which a two-split ring part is connected by a flexible hinge portion. Further, JP-B-5023588 discloses a configuration in which a three-split ring part is connected by a flexible hinge portion, for example.
Furthermore, JP-A-2002-502728 discloses a configuration in which a lock mechanism is provided in a hinge portion, for example.